Hi,
My MechMate #70 have been heavily modified, transforming it from welded frame, to a bolted one.
I am happy with the results but a new problem occurred:
each sequential pass on thick board came "a little bigger" (a slight offset).
I cutted a 19mm MDF board in three 6.5mm pass, each pass is slightly bigger.
All of the sides have the same problem.
I suppose there is a little play on the v-bearings ( a thought I had writing this post :-) ) and the force on the mill push the cut on the outside ...
Any other ideas ?
Sergio

6mm one flute is my most used bit, I have used many times on much harder material than MDF and never had such an evident problems in 6 years.
The problem I had was that the mill was not properly mounted on the ER20 chuck, the same mill gaved no problem once properly mounted. It was my fault